Idle Air Control valve code

I have a 1990 legacy engine and computer in my 69' vw baja bug.

I have been getting codes for the IAC (code #16) that come and go. I have erased all the codes, then took it for a drive and the code comes back. I removed the IAC valve and cleaned it, took it for a drive and the CEL comes back on, throwing a code for the IAC again.

So, I was wondering if there is a way to test to see if its still working?

I unplugged it while idleing and it got all funky with the idle.

I did the engine conversion my self, including the wiring harness modification. But i was very careful to follow instructions and all my connections were soldered, covered in liquid electrical tape, then shrink wraped. So i rule out a bad connection. Also, the harness modification is more like shortening the harness. Cut here, measure X amount of inches, cut again, Solder same color wires back together. Simple.

Thanks,

TSG